Jet lag, medically referred to as ‘desynchronosis’, can be defined as a sleep disorder that results from travelling between two different time zones. Our bodies have natural sleep-wake cycle that is accustomed to the time zone we live in. Similar to how it happens in other chronobiological problem such as erratic shift timings, the body’s clock is out of synchrony due to jet lag. It is directly affected by our natural sleep-wake cycle/light-dark pattern i.e., the patterns of light and dark in our environment. This sleep-wake cycle is called circadian rhythm and disturbance caused to it can result in affected body temperature and disturbed hormone levels along with a variety of other symptoms.
Travelling between two different time zones disrupts the light-dark pattern. Even a difference of a few hours between different time zones is enough to wreak havoc in your body’s sleep-wake cycle. For example, an Indian who travels to Switzerland may receive a wakeup call at 7 am, but his or her body will still function as per Indian timings, where the time will be 1 am.
The effects of jet lag can last for more than a few hours or days. It is because the disturbed hormone levels of the body disturb the normal pattern of the body’s various functions. The disturbed functions normalise only after the body has adjusted well to the new time zone. The speed at which the body adjusts to the new time zone varies from person to person; some people need several days to get accustomed to their new schedule whereas others might take only a few hours or do not experience any disruption at all. Airlines often suggest a recovery rate of one day recover per time zone crossed during the air journey.
[Read: Prognosis of Jet Lag]
Crossing one or two different times zones does not necessarily cause jet lag and its symptoms. Jet lag is especially articulated for airline pilots, crew and people who travel frequently.
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